Method of manufacturing nuts



March 25,1947. I E. A. GREEN 2,418,070

METHOD OF MANUFACTURING NUTS Filed Jun 2, 1944 ZSheets-Sheet 1 INVENTOR.Dm ep A? iezzxv March 25,1941. A EEN 2,418,070

METHOD OF MANUFACTURING NUTS I Filed June 2, 1944 2 Shee ts-Sheet 2INVEN TOR. 22am; 4 fear/v Patented Mar. 25, 1947 METHQD OF MANUFACTURINGNUTS Edward A. Green,

Chicago, IlL,

assignor to Security Machine Products Company, Chicago, lit, acorporation of Delaware Application June 2, 1944!, Serial No. 538,369

(Chm-86) 12 Claims.

This invention relates to a method of manufacturing nuts. Moreparticularly the invention relates to a method of manufacturing locknuts, especially lock nuts of the type shown in my copending applicationSerial Number 501,168, filed September 3, 1943.

An object of the invention is to provide a method of manufacturing nutsefficiently, expeditiously and economically.

In my said copending application Serial No. 501,168 there is disclosed anut which for lock nut purposes has a gradually diminishing diametralresilience from its crown face toward its bearing face while for holdingnut purposes the radial strength of the nut will diminish from itsbearing face toward its crown face in proportion to the load assumed bythe threads of the nut when normally loaded. These features are attainedby increasing the wall thickness and radial strength of the nut towardthe bearing face thereof to reenforce the thread convolutions inproportion to the loads they will bear.

The nut may be formed from a standard threaded hexagonal nut blank byforming in the nut slots extending from the crown face of the nut to thebearing face thereof. The number of slots formed each side of the nutmay be varied as desired under different conditions, but for purposes ofillustration two such slots are shown in each side of the nut. In mysaid copending application Serial No. 501,168 the slots of each pair ofslots extend in the direction of their depth parallel to a radial linelocated intermediate the slots of each pair of slots. The slots diminishin depth from the crown face of the nut toward the bearing face thereofand such diminution in depth is in relation to the load to be assumed bythe threads whenthe nut is normally loaded, that is, the slots are ofless depth where the load is greatest. The slots impart to the nutvarying wall thicknesses and radial strength from the bearing face tothe crown face of the nut and such variation is in proportion to theloads assumed by the nut threads when the nut is normally loaded. Inother words, the wall thickness of the nut at any transverse section isrelated to the load requirements of such section, while those portionsof the nut having the least load requirements are of high diametralresilience for lock nut purposes. After the slots have been formed inthe nut the latter is distorted especially adjacent its crown face tohave a minimum thread pitch diameter substantially less than the threadpitch diameter of the minimum standard bolt to which the nut will beapplied,

wherefore the nut at its transverse sections of greatest diametralresilience and which bear the lesser part of the normal load will havefrictional locking engagement with the bolt threads. When the nut hasbeen so distorted it will be seen that the nut adjacent it crown facewill have an interference or tight fit upon the bolt to which it isapplied.

A further and more specific object of the invention is to provide aneificient and economical method of manufacturing the nut shown in mysaid copending application Serial No. 501,168.

Further and additional objects and advantages not hereinbcfore specifiedwill become apparent during the detailed description which is to follow.Referring to the accompanying drawings,

Fig. 1 is a view, partly in side elevation and partly in section, of anindexing head or apparatus for manufacturing nuts and located on thetable of a milling machine which may be of standard or knownconstruction.

Fig. 2 is a top plan view of Fig. 1, with the fluid motor that actuatesthe lock bolt for the indexing head shown in section.

Fig. 3 is a fragmentary irregular sectional view taken substantially online 33 of Fig. 2, looking in the direction of the arrows.

Fig. 4 is a fragmentary plan View corresponding to the lower right handportion of Fig. 2 but showing certain of the parts in differentrelationship.

Fig. 5 is a plan View of a standard threaded hexagonal nut blank.

Fig, 6 is a view similar to Fig. 5 but shows the nut blank after a pairof slots has been milled in one face of the blank.

v Fig. shows the nut blank after a pair of slots has been milled in eachface of the hexagonal blank.

Fig. 8 is a sectional view of th nut before it is diametrally distortedand is taken along line 8-8 of Fig. 7 looking in the direction of thearrows.

Fig. 9 is a View similar to Fig. '7 but shows the nut blank diametrallydistorted, although the distortion is exaggerated for purposes ofillustration, and

Fig. 10 is a sectional view through the diametrally distorted nut shownin Fig. 9 and is taken substantially on line Iii- 40 of Fig. 9 lookingin the direction of the arrows.

Referring particularly to Figs. 1 to 4 inclusive of the drawings thereis shown a suitable apparatusfor practicing the method and whichapparatus is covered in my copending divisional appli- 7 is a Viewsimilar to Figs. 5 and 6 but 3 cation Serial Number 693,833, filedAugust 30, 1946, ID is the main base of an indexing head embodying theinvention which rests upon a subbase II and is secured to said subbaseII and to the table I2 of a milling machine of well known constructionby means of securing bolts Ila, which pass through slots formed inoutstanding flanges Illa of the main base and through the subbase II andinto the table I2. Nuts III) are secured on the bolts IIa to hold theparts in rigidly assembled relationship. One of the bolts IIa isextended upwardly beyond the threaded portion on which the nut III) ismounted. as indicated at He in Fig. 1, for a purpose later to beexplained and the upper end of this upwardly extended portion IIc ofsaid one bolt He is threaded to receive nuts later to be referred to.The main base II] of the indexing head is provided with an upstandingannular wall Illb, as clearly indicated in Fig. 1. The cutter spindle of'the milling machine is indicated at I3 and a pair .of form millingcutters I4 is mounted on said spindle.

index plate I6 which is rigidly secured to the turret by means of boltsI611. The circumference of the index plate I6 is provided with a seriesof lock bolt receiving notches Ilspaced equally 'circumferentially ofthe index plate and corresponding in number to the number of indexedpositions of the turret.

A look bolt I8 is slidably mounted in a boss formed integral with theupstanding wall Iiib of the base II] and said lock bolt moves radiallyof the turret so that its tapered free end can interflt the notches I!as the latter are successively aligned with the lock bolt. It will beunderstood,

of course, that when the tapered end of the lock bolt'is in a notch Hthe turret I is held positively against indexing movement. The lock boltis extended beyond the outer end of the boss by which it is slidablysupported and projects into thecylinder 20 of a fluid actuated motor.

A piston I9 is secured to the end of the lock bolt I8 within u thecylinder 20 and is responsive to the fluid pressure within the cylinderto move the lock bolt into or out of'locking position.

Fluid conduits 2| and 22 communicate with the opposite ends of thecylinder 20 and alternately serve as inlet or exhaust conduits as thecase may be depending upon whether the lock bolt is being moved intolocking position or into unlocked position by the fluid actuated motor.The conduits H and 22 are connected with a suit-' able control valve,not shown, and the latter in turn is connected to a suitable source ofsupply of pressure fluid. Said control valve may be *manually actuatedby the operator of the machine or it can be correlated with and actuatedby the automatic control mechanism of the milling machine as will bewell understood in the art.

The lock bolt I8 on one side thereof is provided with rack teeth 23which mesh with the teeth of a pinion 24 fixed to the lower end of arockable Vertically extending shaft 25 that is I mounted in thesupporting boss for the lock bolt I8. A disk 26 is fixed to the upperend of the shaft 25 and is shown for purposes of illustration asintegral with said shaft, but it will be understood that said disk couldbe separate from the shaft and merely rigidly connected therewith. Thedisk 25 overlies the upper end of the supporting boss and has pivotallymounted on its upper face an indexing pawl 21 which is controlled by thespring 21a.

It will be seen that when the fluid motor is actuated to move the pistontoward the left hand end of the cylinder 20 as viewed in Fig. 2 and toposition the tapered end of the lock bolt I8 in a notch IV, the rackteeth 23 on the lock bolt act through the pinion 24 to rotate the shaft25 in a clockwise direction and to move the indexing pawl from the dashline position of Fig. 2 to the full line position thereof. On the otherhand, when the fluid motor is actuated to move the piston I9 toward theright hand and of the cylinder 23 and to disengage the lock bolt fromthe notch I! to free the turret for indexing movement, the rack teeth 23of the lock bolt will rotate the pinion 24 and shaft 25 in ananticlockwise direction, with the result that the indexing pawl will bemoved in an anticlockwise direction from the full line position of Fig.2 into the dash line position thereof.

An adapter 28 is rigidly bolted to the upper end of the turret I5 by thesecuring screws 29 and said adapter is provided on its upper side with aseries of studs 30 spaced circumferentially of the adapter andcorresponding in number to the number of indexed positions of theturret. The studs 30 receive the nut blanks which are to be operated onin the machine as will later be explained. The periphery of the adapter28 adjacent each stud 30 is provided with recesses 3I which are ofgradually diminishing depth toward their lower ends for a purpose laterto be explained. A retainer plate 32 is non-movably mounted on the upperside of the adapter 28 and the circumference of said plate is locatedradially inwardly of the circumference of the adapter 28. The retainerplate 32 is provided in its circumierence with a recess 32a and hassecured to its upper side adjacent said recess a housing 33 whichslidably supports a spring-pressed radially extending pin 34. Thepurpose of the recess 32a and of the spring-pressed pin 34 will bexplained hereinafter.

The base Iii, sub-base II, turret I5, adapter 23 and retaining plate 32are provided with aligned central openings and a cylinder 35 of a singleacting fluid motor is secured in the central opening of the sub-base IIand extends into the central opening of the turret I5, it beingunderstood that said turret rotates about said cylinder. A piston 36 ismounted in the cylinder 35 on the lower end of a vertically extendingpiston rod 31, the upper end of which is provided with a threadedreduced nipple 38 to which is attached a pressure fluid conduit 39. Thepiston rod 3! is provided with an axial fluid passage 40 extending fromthe nipple 38 axially of the rod and terminating within the cylinder 35.Hence it will be seen that when pressure fluid is admitted to theconduit 33 and passage 40 it will enter the cylinder 35 above the piston36 and act on the latter to move said piston and the piston rod 31 in adownward direction. Conversely, it will be understood that when theconduit 39, passage 43 and the interior of the cylinder 35 are incommunication with an exhaust outlet fluid pressure on the piston 36 isrelieved.

Th central hub 4| of a three arm spider is mounted on the piston rod 3'5and is clamped in position thereon between clamping nuts 42 and it,wherefore said spider moves vertically with the piston rod 3?. Thespider is provided with two long radially extending arms 44 and 45, thefree ends of which overlie the path of movement of the studs 31! carriedby the adapter 28. The third arm id of the spider is a short arm andit's free end is located inwardly of the series of studs 39 and overliesthe retaining plate 32. The arms dd, and it of the spider are providedontheir underside with downwardly extending circular projections 4?located at the same radial distance from the piston rod 31 andprojecting through openings formed in the retaining plate 32. Coilsprings it are mounted on the projections ti and extend through saidopenings in the retainer plate and have their opposite ends abutting,respectively, the underside of the spider arms and the upper side of theadapter 23. It

will be seen that when pressure fluid is admitted to the cylinder 35 soas to move the piston 35 and piston rod 3i downwardly that said springs53 will be compressed as the spider moves downwardly. It will also beunderstood that when the pressure fluid is exhausted from the cylinder35 said compressed coil springs will then act to move the spider arms,the piston rod 3'! and the piston 36 upwardly.

The supply and exhaust of the pressure fluid to and from the cylinder 35may be controlled by a suitable valve, not shown, and said valve may beincorporated as part of the valve for controlthepressure fluid to thecylinder 25 if desired and also said valve may be manually actuated bythe operator or it can be correlated into and actuated by the automaticcontrol mechanism of the milling machine.

A. strap id is provided in its left hand end as viewed in the drawingwith an opening through which the upward extension H of the one bolt iiextends and said strap is rigidly clamped in position on said upwardextension of the bolt by means of nuts 59 and El engaging opposite sidesof the strap. The strap 29 is rigidly secured to the retaining plate 32by means of rivets 52 or other suitable securing means and said strapholds the retaining plate 32 against rotation as the turret l5 andadapter 28 rotate relatively thereto. The strap 49 acts as the base forand supports a vertically extending magazine 53 for the nut blanks, saidmagazine being so located as to overlie and align with the studs 39 'asthe latter pass beneath the magazine, wherefore the lowermost nut blankin the magazine can pass out of'the magazine and upon any stud 38passing therebeneath and which does not have a nut blank mountedthereon.

Before describing the operation of the apparatus, the details of whichhave been set forth,

reference will first be made to the nut which is slotted by theapparatus. In Fig. 5 there is disclosed a standard hexagonal threadednut blank which may be. manufactured by any suitable and well knownmanufacturing method. The fact that a standard nut blank can be utilizedin the method of the present invention is a distinct advantage as it ismuch more economical than would be the case were it necessary to makethe nuts from special drawn shapes.

Fig. 6 shows the blank after a pair of slots 54 has been milled in oneface thereof, while Fig. 7 shows the blank after a pair of slots 54 hasbeen milled in each face of the blank.

By reference to Fig. 8 it will be seen that the depth of the slots 5idiminishes from the crown face of the nut toward the bearing facethereof,

wherefore the nut will have higher diametral resilience adjacent thecrown face than it does adjacent the bearing face for the reasons andthe purposes explained in full in my said copending application SerialNo. 501,168.

In milling the slots 54 in the nut blanks the milling cutters M are ofsuch size and are disposed at such radial distance from the face as tocause the cutters to form the bottom of the slots 54 on a curvature toprovide the said diminishing depth thereof from the crown face to thebearing face of the blank or nut. In this connection it will be notedthat the recesses it! in the periphery of the adapter 28 are provided tofurnish clearance for the sweep of the rotating milling cutters 14.

Assuming that the pair of formed cutters It have been secured on thecutter spindle l3 of the milling machine and said spindle is adjusted tothe required radial distance from the periphery of the adapter 28 theoperation of the apparatus will now be explained. A stack of thestandard hexagonal threaded nut blanks B are mounted in the magazine 53and the lowermost blank of the stack will pass onto the stud 3b which isimmediately below the magazine. The operator will cause the lock pin tobe moved to unlocked position and will then manually index the turretand the adapter 28 until all of the studs between the magazine and thecutting position are provided with nut blanks. The operator will thenrestore the lock bolt to locked position and will start the operation ofthe milling machine. The milling cutter M will then operate on the faceof the blank at the cutting station which is parallel to the spindle itto mill a pair of slots fit in such face in the manner usual in millingmachines. When this pair of slots has been milled in said face of thenut blank the lock bolt i8 is retracted to free the turret and suchretracting movement of the lock bolt causes the indexing pawl 27 to movewith th disk 2b in an anticlockwise direction until the end of the pawlengagesthe face F of the nut blank indicated at B in Fig. 2 and pushessaid blank, adapter and turret forward in a clockwise direction one index space, after which the lock bolt is restored to locking position andthe indexing pawl to the full lin position shown in Fig. 2. Thisindexing movement has caused the nut blank which had the pair of slots54 milled therein to move from beneath the end of the spider arm 15 andthe next nut blank to move beneath said arm and into position to have apair of slots milled therein. The indexing of the adapter and turretoccurs each time the lock bolt is retracted after a pair of slots hasbeen milled in a nut blank by the cutters l4. During the cutting or.milling operation andwhen the turret is locked against indexing movementthe piston has been moved downwardly in the cylinder 35 and the spider dhas been moved downwardly and the springs 58 compressed. The arm 45 ofthe spider bears against the upper or crown face of the nut blank inwhich the slots are being milled and holds said blank tightly inposition. The arm M of l the spider engages the nut blank which. isimmediately beneath it and presses said blank securely upon its stud 3!if the blank has not already completely seated on the stud. When thelock bolt [8 is retracted the cylinder 35 is exhausted and the springs48 raise the spider so that the arms 45 and 44 do not contact the nutblanks which are beneath them. The retaining plate 32 isstationary, itwill b recalled, and hence as the adapter 28 indexes with the turretsaid retainer plate will act to prevent the blanks on r the studs 39from rotating. Intermediate the first and second stations or studs 30from the cutting station th retaining plate 32 is provided with therecess 32a, while the sliding springpressed pin 34 is located justbeyond said recess. The pin 3% engages a face of the blank carried bythe stud that is in alignment with the pin and as the indexing movementtakes place said springpressed pin rocks the nut blank in a clockwisedirection on its stud 39 to position an uncut face of the blank adjacentthe periphery of the adapter 28, it being understood that the recess 32ais for the purpose of accommodating the corner of the nut blank duringsuch rocking movement. Inasmuch as the blanks are hexagonal each blankmust travel past the cutting station six times in order for the pair ofslots 54 to be milled in each face of the blank. When the nuts have hadthe slots milled in each face thereof they are removed from their studs38 at a suitable unloading station. located interme diate the cuttingstation and the loading station. The completed blanks may be removedmanually or a suitable automatic mechanism may be employed for suchpurpose.

It will be understood that when empty studs 353 are beneath the magazine53 a new nut blank will position itself upon such stud so that the studsat all times will carry blanks during the operation of the machine.

After the blanks have had the slots milled in each face and the'blankshave been removed from the studs 39 said blanks are distorted bysuitable distorting dies well known in the art, especially adjacenttheir crown face, to have a minimum thread pitch diameter substantiallyless than the thread pitch diameter of the minimum standard bolt towhich the nut will be applied, wherefor the nut at those transversesections of greatest diametral resilience and which bear the lesser partof the normal load will have frictional locking engagement with the boltthreads.

In Fig. 9 the distortion of the nut is shown in exaggerated form. InFig. 9 the circular form of the bore through the nut at the crown faceis indicated by the dash line 55 while the oval form that this part ofthe bore has after distortion along a diametral line is indicated by thefull line 56.

In Fig. 10 the finished nut is shown in section taken along a linepassing through the minimum thread pitch diameter of the distorted nut."

From the foregoing description it will be evident that an emcient andeconomical method of producing lock nuts is provided by the inventionand particularly with respect to the production of the locknut shown inmy said copending application Serial No. 501,168.

It will be understood that the nut blanks function as part of theindexing mechanism and that the adapter 28 and index ring plate it arecorrelated to the size of the blanks and different adapters and ringplates will be used for difierent size blanks. It will also be notedthat the edges of the recesses 3| act when the pin 34 indexes the blanksto cut off any burrs which. may have formed on the blanks.

Although a preferredembodiment of the invention, has been illustratedand described herein, it will be understood that the invention issusceptible of various modifications and adaptations within the scope ofthe appended claims.

Having thus described my-invention, I claim:

1. A method of producing nuts which comprises cutting in the peripheryof a nut blank a plurality of grooves spaced peripherally of the blankand extending from the crown face to the bearing face thereof anddiminishing in depth toward said bearing face to provide high diametralresilience to the blank adjacent said crown face, and then diametrallydistorting said blank to provide it with a minimum thread pitch diameterless than the thread pitch diameter of the standard bolt on which thenut would be used.

2. A method of producing nuts which comprises cutting in each side faceof a polygonal nut blank grooves extending from the crown face to thebearing face thereof and diminishing in depth toward said bearing faceto provide high diametral resilience to the blank adjacent said crownface, and then diametrally distorting said blank to provide it with aminimum thread pitch diameter less than the thread pitch diameter of thestandard bolt on which the nut would be used.

3. A method of producing nuts which comprises cutting in the peripheryof a nut blank a plurality of peripherally spaced pairs of groovesextending from the crown face to the bearing face thereof anddiminishing in depth toward said bearing face to provide high diametralresilience to the blank adjacent said crown face, and then diametrallydistorting said blank to provide it with a minimum thread pitch diameterless than the thread pitch diameter of the standard bolt on which thenut would be used.

4. A method of producing nuts which comprises cutting in the peripheryof a nut blank a plurality of peripherally spaced pairs of groovesextending from the crown face to the bearing face thereof anddiminishing in depth toward said bearing face to provide high diametralresilience to the blank adjacent said crown face and with the grooves ofeach pair parallel to each other and to 'a' radius of said blank, andthen diametrally distorting said blank to provide it with a minimumthread pitch diameter less than the thread pitch diameter of thestandard bolt on which the nut would be used.

5. A method of producing nuts whichcomprises cutting in each side faceof a polygonal nut blank a pair of grooves extending from the crown faceto the bearing face thereof and diminishing in depth toward said bearingface to provide high diametral resilience to the blank adjacent saidcrown face, and then diametrally distorting said blank to provide itwith a minimum thread pitch diameter less than the thread pitch diameterof the standard bolt on which the nut would be used.

6. A method of producing nuts which comprises cutting in each side faceof a polygonal nut blank a pair of grooves extending from the crown faceto the bearing face thereof and diminishing in depth toward said bearingface to provide high diametral resilience to the blank adjacent saidcrown face with the grooves of each pair parallel to a radial line ofthe blank that is perpendicular to the respective blank side face, andthen diametrally distorting said blank to provide it with a minimumthread pitch diameter less than the thread pitch diameter of thestandard bolt .on which the nut would be used.

7. A method of producing nuts which comrises spacing the axis of arotating cutter of predetermined diameter a predetermined distance fromthe axis of a nut blank and causing .the cutter to cut peripherallyspaced axially extending grooves in the blank with the sweep of thecutter causing said grooves to be of diminishing depth from the crownface of the blank toward the bearing face thereof to provide highdiametral resilience to the blank adjacent said crown face, and thendiametrally distorting said blank to provide it with a minimum threadpitch diameter less than the thread pitch diameter of the standard bolton which the nut would be used.

8. A method of producing nuts which cornprises spacing the common aXisof a plurality of rotating parallel cutters of predetermined diameter apredetermined distance from the axis of a nut blank and causing thecutters to out successively peripherally spaced axially extendinggrooves in the blank with the sweep of the cutters causing said groovesto be of diminishing depth from the crown face of the blank toward thebearing face thereof to provide high diametral resilience to the blankadjacent said crown face, and then dfametrally distorting said blank toprovide it with a m nimum thread pitch diameter less than the threadpitch diameter of the standard bolt on which the nut would be used.

9. A method of producing nuts which comprises spacing the common axis ofa plurality of rotating parallel cutters of predetermined diameter apredetermined distance from the axis of a nut blank and with the planesof said cutters parallel to a radius of aid blank and successivelcausing the cutters to cut peripherally spaced axially extending groovesin the blank with the sweep of the cutters causing said grooves to be ofdiminishing depth from the crown face of the blank to the bearing facethereof to provide high diametral resilience to the blank adjacent saidcrown face, and then diametrally distorting said lank to provide it witha minimum thread pitch diameter less than the thread pitch diameter ofthe standard bolt on which the nut would be used.

10. A method of producing nuts which comprises spacing the axis of arotating cutter of predetermined diameter a predetermined distance fromthe axis of a polygonal nut blank and then causing the cutter tosuccessively cut in each side face of the blank an axially extendinggroove with the sweep of the cutter causing said groove to be ofdiminishing depth from the crown face of the blank toward the bearingface thereof to provide high diametral resilience to the blank adjacentsaid crown face, and then diametrally distorting said blank to provideit with a minimum thread pitch diameter less than the thread pitchdiameter of the standard bolt on which the nut would be used.

11. A method of producing nuts which comprises spacing the common axisof a plurality of rotating cutters of predetermined diameter apredetermined distance from the axis of a polygonal nut blank andcausing the cutters to successively cut a plurality of axially extendinggrooves in each side face of the blank with the sweep of the cutterscausing said grooves to be of diminishing depth from the crown face ofthe blank to the bearing face thereof to provide high diametralresilience, and then diametrally distort- .ing said blank to provide itwith a minimum thread pitch diameter less than the threadpitch diameterof the standard bolt on which the nut would be used.

3.2. A method of producing nuts which comprises spacing the common arisof a pair of parallel rotating cutters of predetermined diameter apredetermined distance from the axis of a polygonal nut blank andcausing the cutters to cut successively in each side face of the blank apair of axially extending grooves with the sweep of the cutters being inplanes parallel to the radius of the blank that is perpendicular to therespective side face thereof and causing said grooves to be ofdiminishing depth from the crown face of the blank to the bearing facethereof to provide high diametral resilience to the blank adjacent saidcrown face, and then diametrally distorting said blank toprovide it witha minimum thread pitch diameter less than the thread pitch diameter ofthe standard bolt on which the nut would be used.

EDVZARD A. GREEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,714,072 Brownlee May 21, 19291,033,837 Smith July 30, 1912 1,198,967 Stempert Sept. 19, 1916

